1. Field of the Invention
The present invention relates to inspection apparatus such as line width measuring apparatus and more particularly, to a method of recognizing, for example, inspection reference positions on a subject to be inspected such as a substrate and an inspection apparatus using the method.
2. Description of the Related Art
FIG. 3 is a block diagram showing an example of construction of a line width measuring apparatus.
A line width measuring apparatus, which measures a width or a gap in a thin-film or a thin-film pattern formed on a substrate, and an inspection apparatus, which inspects a defect or a scratch on a substrate, are required to detect the error before starting an inspection, because an individual substrate as an inspection object has a dimensional error or a tolerance in a pattern formation, respectively.
To resolve above problem, the line width measuring apparatus or the inspection apparatus recognizes a reference pattern, for example, such as alignment mark on a substrate as an inspection object, the reference pattern is produced as same process as the measured pattern at the same time. And then, an inspection position to the reference position in the apparatus which recognized the reference position is corrected. Thereby, if an error in a substrate occurs, a normal inspection is conducted.
A technique as above is disclosed in, for example, JP-A-8-222611 (see pages 5 and 6 and FIG. 1) and JP-A-9-36202.